Predation by Nesidiocoris Tenuis on Bemisia Tabaci and Injury to Tomato
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BioControl (2009) 54:237–246 DOI 10.1007/s10526-008-9164-y Predation by Nesidiocoris tenuis on Bemisia tabaci and injury to tomato Javier Calvo Æ Karel Bolckmans Æ Philip A. Stansly Æ Alberto Urbaneja Received: 16 January 2007 / Accepted: 14 April 2008 / Published online: 10 May 2008 Ó International Organization for Biological Control (IOBC) 2008 Abstract Tomato is the most important vegetable considered a pest because it can feed on tomato crop in Spain. The mirid bug Nesidiocoris tenuis plants, causing necrotic rings on stems and flowers (Reuter) commonly appears in large numbers in and punctures in fruits. Our objectives were to protected and open-air tomato crops where little or no evaluate predation by N. tenuis on sweetpotato broad-spectrum insecticides are used. Nesidiocoris whitefly Bemisia tabaci Gennadius under greenhouse tenuis is known to be a predator of whiteflies, thrips conditions and establish its relationship to N. tenuis and several other pest species. However, it is also feeding on tomato. Two different release rates of N. tenuis were compared with an untreated control (0, 1 and 4 N. tenuis plant-1) in cages of 8 m2. Hanlding editor: Eric Lucas. Significant reductions of greater than 90% of the whitefly population and correspondingly high num- This research is part of an internal R&D project conducted at bers of N. tenuis were observed with both release Koppert Biological Systems S.L. in Spain. The main goal was rates. Regression analysis showed that necrotic rings to improve control of Bemisia tabaci in protected crops of southeastern Spain by bringing on a new biological control on foliage caused by N. tenuis were best explained by agent. the ratio of B. tabaci nymphs:N. tenuis as predicted by the equation y = 15.086x - 0.6359. J. Calvo Á A. Urbaneja R & D Department, Koppert Biological Systems S.L., Finca Labradorcico del Medio, s/n. Apartado de Correos Keywords Miridae Á Whitefly Á Biological control Á 286, 30880 Aguilas, Spain Zoophytophagy K. Bolckmans R & D Department, Koppert B.V., Veilingweg 17, 2651 BE Berkel en Rodenrijs, The Netherlands Introduction P. A. Stansly Tomato (Lycopersicon esculentum Mill.) is the most University of Florida-IFAS, 2686 State Road 29N, important vegetable crop in Spain, with a production 34142 Immokalee, FL, USA area of close to 60,000 ha in 2002 and a total A. Urbaneja (&) production of 4 million metric tonnes. Almost 28% Unidad de Entomologı´a, Centro de Proteccio´n Vegetal y of this volume is produced in the Comunidad Biotecnologı´a, Instituto Valenciano de Investigaciones Auto´noma de Murcia and in the adjacent province Agrarias (IVIA), Carretera de Moncada – Na´quera Km. 4,5, 46 113 Moncada, Valencia, Spain of Almerı´a (INE 2002). In both regions, tomatoes are e-mail: [email protected] grown primarily in plastic covered greenhouses. In 123 238 J. Calvo et al. recent years, the most harmful pest of tomato in these et al. 1976; Kajita 1978; Malausa 1989; Malausa and regions has been the whitefly Bemisia tabaci (Gen- Henao 1988; Vacante and Grazia 1994). The necrotic nadius) (Hem.: Aleyrodidae). This pest causes rings on the flower petiole can result in under certain damage by sucking the sap, thus weakening the conditions on floral abortion (Calvo and Urbaneja plant, and by secreting large amounts of honeydew 2004;Sa´nchez et al. 2006). Intensity of injury to that favour the appearance of sooty mould. However, tomato has been observed to decrease with increased the greatest impact on tomato is due to its role as availability of prey (Arno´ et al. 2006). vector of tomato yellow leaf curl virus (TYLCV) The aim of the present work is to evaluate the (SIFA 2004). Serious economic losses have been efficacy of N. tenuis in controlling B. tabaci and to caused in Spain by this geminivirus since its appea- characterize damage to tomato. This information could rance in the 1990s (CARM 1996). Consequently, then form a basis for management of N. tenuis that will permissible population levels of B. tabaci are mini- optimize benefits derived from predation on B. tabaci mal, such that implementation of biocontrol based while minimizing damage to the tomato crop. IPM programs is difficult (Stansly et al. 2004). Nevertheless, interest in biological control continues to increase in Spain (Castan˜e´ 2002; van der Blom Materials and methods 2002), thanks in part to adaptation of TYLCV- tolerant varieties, development of pesticide resistance Test facilities (Cahill et al. 1996; Elbert and Nauen 2000) and successful use of natural enemies against this pest The experiment was conducted in a 40 9 10 m air (Stansly et al. 2004, 2005a, b; Urbaneja et al. 2002; inflated double layered polyethylene covered Quonset Calvo and Belda 2006). style greenhouse equipped with pad-and-fan cooling The parasitoid Eretmocerus mundus Mercet (Hym.: and diesel-fired heating, located at the Koppert Aphelinidae) and the predator Nesidiocoris tenuis Biological Systems S.A. facilities in A´ guilas, Murcia, Reuter (Hem.: Miridae) (Sa´nchez et al. 2003a, b; van Spain. The plastic tunnel was accessed through a der Blom 2002) are endemic natural enemies of double door and was divided into 36 experimental B. tabaci that commonly appear in tomato crops in cages constructed of ‘‘anti-thrips’’ polyethylene Southern Spain. The biology, behaviour and effec- screening with 220 9 331 lm interstices supported tiveness of E. mundus is well documented (Stansly by heavy guy wires connected to the greenhouse et al. 2004, 2005a, b; Urbaneja and Stansly 2004), and superstructure. Each experimental cage was 4 9 2 9 this parasitoid is mass-reared and released to control 3.5 m (l 9 w 9 h) and covered on the floor with a B. tabaci in greenhouse vegetable crops in this region 2 mm-thick woven white polyethylene ground cloth. (Urbaneja et al. 2003a). In contrast, only limited Each cage was accessed by an independent door research has been reported on the potential of N. tenuis secured with a zipper. Twelve cages were used for the for augmentative biological control of B. tabaci. present study, six on either side of the centre aisle. Often cited with regard to its polyphagous habit Dataloggers (model HOBO H8 RH/Temp, Onset (Goula 1985; Urbaneja et al. 2005) or zoophytopha- Computer Company, Bourne, MA, the USA) were gous behaviour (Dolling 1991), N. tenuis has been placed in four different cages to record temperature observed to contribute to the control of whiteflies, and relative-humidity. thrips, leafminers, spidermites, and Lepidoptera spe- cies in greenhouses (Arzone et al. 1990; Calvo and Environmental conditions Urbaneja 2003; Carnero et al. 2000; Marcos and Rejesus 1992; Solsoloy et al. 1994; Torreno 1994; The average temperature during the experiment ranged Trottin-Caudal and Millot 1997; Vacante and between 26°C, on 3 October 2002, to 20°C, on 16 Benuzzi 2002; Vacante and Grazia 1994). However, January 2003, with an absolute minimum and maximum N. tenuis has also been classified as a pest of tomato of 14.5 and 38.3°C respectively during the test period (Male´zieux et al. 1995) due to feeding damage such (Fig. 1A). Average relative humidity ranged from 84%, as necrotic rings in both leaf and flower petioles, and on 31 October 2002 to 65% on 16 January 2003 with whitish halos on fruit (Arno´ et al. 2006; El-Dessouki absolute values of 100 and 22% respectively (Fig. 1B). 123 Predation by Nesidiocoris tenuis on Bemisia tabaci 239 Fig. 1 A Temperature ( ) A 40 and relative humidity (B)in the greenhouse during the experiment 30 C) ° 20 Temp ( 10 0 123456789101112131415 Trial Week Mean Max Min B 100 80 60 RH (%) 40 20 0 123456789101112131415 Trial Week Mean Max Min Plant and pest management other plant, densities. Crop cultivation techniques typical of tomato greenhouse-cultivation in Spain Tomato seeds variety ‘Boludo’, tolerant to TYLCV were followed: a trellis of two wire-guides for each and TSWV (Seminis Vegetable Seeds Europe plant to which the main stem was trained using black Enkhuizen, The Netherlands), were sown on 1 polyethylene string, weekly pruning of secondary September 2002. Seeds were deposited in 5.4 cm2 shoots, application of a standard nutrient solution for cells in expanded polystyrene trays of 11 9 19 cm tomato by means of an automated-irrigation system filled with peat. On 27 September, seedlings were with an irrigation frequency adjusted to accumulated transplanted into polyethylene 6.3 l flowerpots filled radiation (800 W m-2), and an irrigation time of with cocopeat (coir) growing medium and placed 8.5 min. inside the experimental greenhouse in two rows of 5 plants per cage or 1.25 plants m-2. Plant densities in Whiteflies and predators commercial tomato crops in southern Spain vary from 1.25 to 3 plants m-2. However therefore, the release Bemisia tabaci adults came from an experimental rates for all the insects were calculated in individuals colony located in A´ guilas and identified as B. tabaci per plant, so results could easily be transformed to biotype ‘‘Q’’ based on DNA analysis (J.L. Cenis, 123 240 J. Calvo et al. IMIDA La Alberca. Murcia, Espan˜a, Personal adults, and necrotic rings during the course of the trial Communication). Less than 4-day-old N. tenuis were calculated (Stansly et al. 2005a, b). The resulting adults were obtained from an experimental colony estimates of insect and damage accumulated 9 days maintained at 25°C and 75% RH, maintained on (= area under the weekly incidence curve) was then tobacco plants and fed with Ephestia kuehniella subjected to a one-way analysis of variance joined with Zeller (Lepidoptera: Pyralidae) eggs. The sex-ratio of a Tukey’s test for mean separation (P \ 0.05).